DETAILED VERIFIED ANSWERS /A+ GRADE ASSURED(LATEST UPDATE)
How is the Meridian oriented when we look at a patient? - (correct answer) Right to left 180-0
Find the slab off and which eye it goes on:
OD RX is +1.50
OS RX is +5.25
OC ht difference is 8mm -
(correct answer) OD 8x1.50/10= 1.2
OS 8x5.25/10= 4.2
4.2-1.2= 3.0 prism On OD lens (most minus)
How is the meridian oriented when we look at the back of a lens? - (correct answer) Left to right 0-180
The power of a lens is -4.00 and the base curve is +6.00, what is the backside curve? - (correct answer) P-F=B // -
4.00-6.00= -10.00
A person is looking out of a plus lens below the optical center. What type of prism are they experiencing? - (correct
answer) base-up
Which lines on a lensometer represent the cylinder power? - (correct answer) thick lines
An image appears toward the ______ of a prism. - (correct answer) Apex
If a person is looking below the optical center of a minus lens, what type of prism are they looking through? - (correct
answer) Base down
There is a lens that measures +9.50 for the base curve and the ocular curve is a -2.25, what is the power of a lens? -
(correct answer) F+B=P // +9.50+(-2.25)= +7.25
What is the formula to find the power of a lens? - (correct answer) F+B=P
Find the power at the 90 deg meridian
+4.00 -3.00 x135 - (correct answer) +2.50
Find the power at the 90 deg meridian
-4.00 -1.50 x45 - (correct answer) +4.75
Find the slab and which eye it goes on:
OD: -1.00 -0.50 x90
OS: -3.50 -1.25 x180
OC ht diff is 11 - (correct answer) OD: -1.00x11/10= 1.1
OS: -4.75x11/10= 5.2 (transpose for 90 meridian)
5.2-1.1= 4.1 prism
Goes on the left lens (most minus)
What is reverse slab and which eye does it go on? - (correct answer) Premade slab off lenses only available in CR39.
Goes on the most plus or least minus eye.
Hyperopia, Presbyopia, and Aphakia - (correct answer) What 3 types of refractive errors does a plus lens correct?
, There is a lens that has a base curve of +2.25 and a back curve of -12.25, what is the power of a lens? - (correct
answer) F+B=P || +2.25+(-12.25)= -10.00
Where is the cornea located? - (correct answer) clear area over the iris
How do you transpose an RX? - (correct answer) Algebraically add the sphere power and the cylinder power to get
the new sphere power, use the same cylinder power but switch the sign, and add/subtract 90 degrees to the axis
Where is the sclera located? - (correct answer) The white part of the eye
Where does the aqueous humor drain? - (correct answer) Canal of Schlemm
What is age-related macular degeneration (AMD)? - (correct answer) loss of central vision
What is compound myopic astigmatism? - (correct answer) Both meridians are myopic (minus)
What is compound hyperopic astigmatism? - (correct answer) Both meridians are hyperopic (plus)
A bifocal is generally fit at what height? - (correct answer) At the lower lid
How far apart are the markings on a progressive lens? - (correct answer) 34mm
What was the first material used to make anti-reflective? - (correct answer) Magnesium Flouride
What is the Abbe value for basic plastic? - (correct answer) 60
What is Simple Hyperopic Astigmatism? - (correct answer) One meridian Plano and the opposite one hyperopic
(plus)
absence of the crystalline lens of the eye - (correct answer) Aphakia
Which lines on a lensometer represent the sphere power? - (correct answer) Thin narrow lines
The actual powers of a lens are -5.50 x65 and -7.25. What is the rx? - (correct answer) -5.50 -1.75 x65 // Find the
difference between both meridians and that is your cylinder power.
Transpose this rx: +1.50 +1.50 x41 - (correct answer) +3.00 -1.50 x131
What is the formula to find the focal length? - (correct answer) f=1/D
Slab off prism - (correct answer) What is another term for bicentric grid?
What does abbe value represent? - (correct answer) Dispersion of a lens
The power of a lens is +3.50, what is the focal length? - (correct answer) f=1/D
f=1/3.50
f=0.285m
On a non-coated plastic lens, how much light is lost as it passes through the lens? - (correct answer) 8% (4% on
each surface)
What percent of the add is in the intermediate section of a trifocal? - (correct answer) 50%